Point-to-point steering of electromagnetic radiation may be used in many applications, often in such a fashion that may require adjustment over time. For example, the ability to provide precise beam pointing may be important in systems where beam alignment and target tracking are required (usually optical, at least partially collimated), such as free-space optical communications (e.g., “laser comm,” such as ship-to-ship, ground-to-air, etc.), countermeasures, directed energy weapons (e.g., “laser cannons”), and/or fiber optic switching devices (such as routers). Such electro-optical systems may benefit from point-to-point steering with rapid pointing ability, compact size, and/or light weight.
With increasing demands for compact, robust, and/or cost-effective devices for beam steering, Risley Prisms (typically made up of pairs of wedge prisms) have been used for their high degree of accuracy and stability. Their utility, however, may be limited by relatively small deflection angles and/or poor size scaling properties (for example, due to bulky prismatic elements) where wide angles and modest/large apertures are required. Other mechanical methods to steer the light, such as tilting a mirror or gimbal mount, may also present difficulties for many applications due to their size, weight, and/or speed. Non-mechanical (inertialess) beam steering options may also be possible, such as optical-phased-arrays formed by LC spatial-light-modulators or electrowetting devices, switchable volume holograms, blazed gratings, birefringent prisms, microlens (lenslet) arrays, and Micro-Electro-Mechanical Systems (MEMs) mirrors. However, many of these applications may be limited by relatively low throughput, high absorption/loss/scattering, small steering range/resolution/aperture, and/or large physical size/weight.